The existing back light module usually includes a light guide plate (LGP), a rear panel, a PCB (Printed Circuit Board), and a plurality of LEDs (Light Emitting Diodes) fixed on the PCB. Generally, there are two following kinds of fixed modes of the PCB: a, a heat conductive adhesive tape is pasted between the PCB and the rear panel; b, a screw is used to lock and attach the PCB and the rear panel. Wherein, the advantage of mode a is that the heat conductive adhesive tape can fill in the gap between the two interfaces, but the cost of the heat conductive adhesive tape is high. The mode b can reach the close contact of the two interfaces. The cost of the screw is lower than that of the heat conductive adhesive tape. However, the PCB is generally narrow and the adopted screw is relatively small, and thereby causing difficulties on locking and attaching task.
Besides, in the known side-light type back light module, the LGP usually positions left and right ends only by the rear panel to ensure a distance between the LGP and the LED surface. After the LGP is heated and expands, the swell capacity of the LGP in the central position of the module is the maximum, making a light input surface of the LGP directly support the LED surface. Since the surface temperature of the LED is extremely high, the LGP is easily melted.
Therefore, the technical problems including assembling difficulty, high cost, and easily melting of the LGP exist in the back light module of the prior art.